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DIY Lifepo4 Battery - Component Checklist

Mrdanielmh

Solar Enthusiast
Joined
Apr 19, 2020
Messages
177
Good morning everyone!

I've read so much information and done a lot of research about Lifepo4, and I think I'm ready to purchase. However I just want to double check that I have exactly what I need!

Requirements: A Lifepo4 Battery for my campervan, all 12v.
Equipment: I currently have the following equipment

315W Solar Panel
Victron 100/30 MPPT
Victron Orion 12 12 30 DC2DC
Victron Smart Protect 65a
Victron Smart Charger 30a

What I am looking at now if getting the pieces for my battery! I was toying with the idea of buying of the shelf, for example the TN100 is well priced in the UK (£660). However I have started to look into DIY more because I think I can get more for my money. In terms of size, we were looking around 100AH, but again I think I can get more!

Parts List - This is where I need help/confirmation!

4 x Cells - https://tinyurl.com/y99we57h (100ah) or https://tinyurl.com/y77xhhsh (280ah)
I then need Busbars and bolts!
Tape to tie it altogether
BMS - I don't think I need a BMS because I can use the Victron SP65a to stop over voltage, and possibly the other gear for under voltage? I should be able to work low temperature disconnect work within this system too?
Battery Balancer - I'm struggling to find one in the UK, any recommendations?

All of the above would give me a functioning battery? Is there anything else I need to consider and be aware of?

Thank you all!
 
Sounds like a plan! Four comments:

See if the cells come with busbars and bolts. Some do.
BMS is highly recommended for balancing as well as various protections.
With a BMS no separate balancer is needed.
Don't forget fuses/breakers!
 
All of the above would give me a functioning battery? Is there anything else I need to consider and be aware of?
Your list of equipment that you already own seem worthy of more than a 100ah battery.
But, hopefully you've determined your energy use and storage needs.

And the BMS is rated for the current going thru the BMS, NOT the size of the battery. That is why a BMS would be rated in amps, not amp hours.
 
Sorry, I'm no expert on BMS selection. Depending on the max load you expect, it may be better to go with a more moderately sized BMS and a relay to cut the battery. Will Prowse has videos that explain this.
 
Thank you everyone, I think I understand everything a bit better now!

4 Cells in Series (4S)
Busbars and Bolts
BMS - Rated for maximum throughput on battery
 
For your under temp, Victron sells a battery temp/voltage sensor that will tie into your 100/30 Smart Battery Sense, I think. You can then set your ranges across the battery (not individual cells).

Also, just throwing this out there, that 100/30 (35?) really is a nice and small unit but if you're dead set on staying 12V, you'll be limited to 360W of charging/load so take that into consideration when you add up your use and battery size. I would consider going with a 24V if you'll be building anything ~ 2400Wh or larger. smaller wires, less chance to hit your head on that 360W limit, room for expandability (another panel) faster charge potential.

IF you consider 24V (or convert this to a 12V) I've been eying this battery pack
Looking forward to seeing how it turns out.
 
Nice, I'm looking at a similar setup, but will go with the Renogy DC-DC 50a with mppt instead of more wiring along with the 12v-4s (most likely 280ah), but based on everything I've read, invest in a BMS.
 
That is exactly right, Renogy maximum is 25V - Basically their own panels. Mine is 33!
 
I'm still considering swapping out my 75/15 for it but only because of my limited charge requirements.
 
Wow, i did not see that coming with it being a 50A charger. Thanks.
25v is REALLY weak.
And not only that, it's called a 50A but i believe it's only 25A solar mppt and 25A dc dc charger.

This is what one reviewer wrote on Amazon about it.

"Excellent for my RV, it has the ability to charge lithium batteries, by solar panels or DC-DC. Only downside is it’s only allowed up to 25Amp per charging options not like the 50amp I thought it would be"
 
FYI: RUN from Renogy ! It is the LOW Fruit on the shlock tree !
They advertise a LOT, they have slick promo's BUT service SUCKS, warranty stuff is a bugger and often they mis ship, or lose shipments and other stuff.. There are HUNDREDS of reviews with complaints and several folks here have been fookered by them one way or another.

IF you want DECENT Value brands of equipment, look at EPEver, MPP-Solar, GROWATT and so on.
Victron is Tier-1 Quality product, which is premium good stuff.
 
I like the choice of Victron stuff.. For the low Temp Disconnect, they do a small magic box, which connects to the 100/30 via Bluetooth, and provides the charger, with the temp, so it can stop the charging at the temp you specify
https://www.amazon.co.uk/Victron-En...s=victron+battery+sense&qid=1587727688&sr=8-1

The other option, is to incorporate the Low Temp cutoff, into a BMS. Will did a review of this one.
https://batteryhookup.com/collectio...ff?rfsn=2267412.b1bf25&variant=31523195289732
Which goes to 120A I believe. Beware though, Battery Hookup is a US company, and ships via UPS I think, so you will get stung for an additional £25 in tax as it enters the UK, making the whole thing over the £100. If you have got the Victron Smartsense, (like I have) you could use any larger BMS, like one from Daly..
https://www.ebay.com/itm/4S-80A-100...hash=item1a2da0dfbc:m:mGLIawWFRZ_q-9B2X8x0hQw

Something like this goes to 300A if you are running large loads on bigger batteries
https://www.amazon.co.uk/Iycorish-L...=daly+bms+4s+200a&qid=1587728121&sr=8-2-fkmr0

All the BMS will take care of balancing..

some VHB Tape to stick the cells together
A box https://www.ebay.co.uk/itm/TREM-N01...420468?hash=item3b084e4ff4:g:YMsAAOSwkXdaxi8B

Battery terminals https://www.ebay.co.uk/itm/6mm-Bras...120312?hash=item288b801ab8:g:u1cAAOSwd1deBx9e

Some decent Welding cable 35mm (2AWG)
Lugs https://www.ebay.co.uk/itm/Copper-T...hash=item1cdc8474d8:m:mNn7BZZufditXWwsF2FnmYg

The list goes on......... and on..... and on............ :)
 
Great post! thank you for the advice. I've gone for the 120a from Alibaba in the end! Thanks for the links, very helpful
 
I did end up buying the renogy dc dc 40a charger from Canada website. It was only 180 cdn free shipping with coupon. Heck of a lot better than 500 for a Sterling.


Plus Will liked the renogy so that's good enough for me.
 
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